In the first rush of apps (applications) for mobile devices we've seen a veritable bonanza of all types of marine-related options.

Now that there's been time for the dust to settle and many of these apps have been upgraded, we thought it was time to revisit some of the more popular ones.

This month the navigation apps are back in the spotlight. Your decision to buy here is going to be governed by two factors. The first is a personal preference: do you prefer Raster Charts (essentially copies of the original paper charts in electronic format) or Vector Charts (layered electronic charts)? The second is budget.

We tested four products for comparison: iSailor and Navionics in the Vector arena, and Memory Map and iNavX in the Raster court.

iNavx (Raster charts/US$50)This is essentially a full function chart-plotting app and is exclusive to Apple devices. The app is at the top end of the range, dollar wise, and comes with no charts. Chart packs are available through the X-Traverse website. A US$10/ annum subscription gives you access to the world but the prices are hefty for the chart bundles.

Memory Map (Raster charts/US$6.95)Memory Map has great functionality and can also be run on your PC or Mac and synced with your mobile device (Android and Apple). It's great value and the charts are a reasonable price. The pack for the East Coast of Australia for example is $49.99US with a license for two mobile devices. Memory Map also has add-ons for AIS and Autopilot control.

iSailor (Vector charts/Free)This is from Transas and is free to download. Chart folios can be downloaded through the app. As an example, the Chart Folio for the Australian East coast or the New Zealand folio (which includes Tonga) are $30.99US each. iSailor is a great chart plotting app with good functionality and a user-friendly layout.

Navionics (Vector charts/US $50)The Navionics app is perhaps the best value for money. It gives you access to charts from the Indian Ocean across Australasia and most of the SW Pacific. Despite a number of upgrades though, the Navionics app is not a fully functional chart plotter but it's on its way according to the Navionics website.